Re: [rfc] Ignore Fsync Calls in Laptop_Mode

[D. Jansen]

On Fri, May 20, 2011 at 5:39 AM, Dave Chinner <david@xxxxxxxxxxxxx> wrote:
> On Thu, May 19, 2011 at 03:34:46PM +0200, Dennis Jansen wrote:
>> This is my first proper kernel code proposal so please bear with me!
>>
>> =Summary for busy kernel hackers=
>> Problem: laptop_mode wants to keep applications from waking the hard
>> disks but fsync calls can "sneak through". (IMHO this is a bug.)
>>
>> Proposed solution: Pretend the fsync was executed and successful.
>> Insert two lines into the fsync and fdatasync calls in fs/sync.c:
>> if (unlikely(laptop_mode))
>> Â Âreturn 0;
>
> No, no, no, no, no, no, no, no, no, no.
>
> There is _absolutely no justification_ for putting people's data at
> risk like this. ÂIf you want to do make fsync/fdatasync calls
> no-ops, then go install libeatmydata on your systems. It's your
> data, and you make the decision to risk it, not us.

1. I thought I (may) make that decision by using laptop mode.
2. libeatmydata would _always_ be active.
3. A lib doesn't fix the ordering guarantee problem.
4. It's clear that it's not the right code. (And it is a rfc and my
first one, too...)

Any suggestions?

Thanks!

Dennis
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/